Factors associated with bone metastasis in breast cancer: a preliminary study in an Indonesian population.

AIM: to know the characteristics of breast cancer patients with bone metastasis and its risk factors. METHODS: this was a cross-sectional study on breast cancer patients in Dharmais Cancer Hospital between 1998 and 2002. Data were retrieved from medical records and consisted of age, history of hormonal contraceptive use, histopathological type, estrogen receptor (ER) and progesteron receptor (PR) expression, c-erbB-2 and cathepsin D expressions. RESULTS: a total of 197 cases were recruited between the study period. Almost all patients were women with a mean age of 47 years old. The majority of patients were between 36 and 55 years old (69.1%) with a peak between 46 and 50 years. About 70% of the patients had already had advanced diseases (III and IV). Invasive ductal carcinoma was the commonest histopathological type (80%). The expression of ER, PR, c-erbB-2, and cathepsin D were evaluated in 55 patients. Metastases were found to occur in bone (24.4%), lungs (20.8%), and liver (10.7%). Among patients with bone metastasis, 36 patients ((75%) were more than 40 years old and 32 (66.7%) had invasive ductal carcinomas. There was a significant correlation (p=0.011) between bone metastasis and histopathological type. No significant correlation was found between the use of hormonal contraceptives, ER/PR expression, c-erbB-2 and cathepsin D and bone metastasis. CONCLUSION: most breast cancer patients came in an already advanced stage, either locally or distant metastasis. The most common site of metastasis was the bone, followed by lungs and liver. Histopathological type of invasive ductal carcinoma was associated to the higher incidence of bone metastasis. Further studies are needed to identify patients with high risk of bone metastasis. There is also a need to evaluate predictive factors for the occurrence of bone metastasis at earlier stage.